1. Field of the Invention
The present invention relates to a linear motor system.
2. Description of Related Art
Linear motor systems have been widely employed in conveyor carriages of physical distributing apparatuses, transport apparatuses acting as machine tool loaders, or the like in order to drive the apparatuses. A ground primary linear motor system is proposed as the linear motor system in which a primary coil is disposed on a fixing side (for example, a ground side) and a permanent magnet is disposed on a mover side (for example, see U.S. Pat. No. 8,796,959 and WO2010/024234). In the linear motor system, for example, motor controllers control a plurality of motors, and an integrated controller controls the plurality of motor controllers. A magnetic sensor that detects a position of a mover acting as a magnet array is disposed between the motors. The integrated controller specifies a motor controller that is suitable for a position of a mover based on a result detected by the magnetic sensor, and supplies a control instruction (traveling command) to the specified motor controller.
When control is complicated in the linear motor system, it is occasionally difficult to allow the mover to stably travel. For example, since a number of the motor controllers to be allocated to one integrated controller is limited, the system is enlarged and the number of motors increases in some cases. In this case, for example, a host controller (a linear controller) is provided to the plurality of integrated controllers, and the host controller totally controls the plurality of integrated controllers. When the mover lies across a zone associated with one integrated controller and a next zone, a delay of a signal might occur between one integrated controller and an integrated controller for the next zone due to a difference of an information transmission path. The occurrence of such a signal delay causes a control variation, a delay, and an increase/decrease in a load according to a position, and thus a smooth transfer of the mover is hindered.